I have a 2008 Mustang. The heat/Ac fan works intermittently, and of course always at the most inopportune time, like yesterday when it was 19 degrees. I can feel the heat, but the fan will not come on, even when turned up to 4. Took it to the local Ford dealer, they could not replicate the problem, of course, so I had them replace the blower motor for the fan. Took it home, next day the same thing - no fan. Took it back to dealer, where they were able to replicate the "new" fan not working and they changed out the relay wires. Worked for a day or two, and has now gone back to the on again/off again cycle of no fan. Started to have the same issue at the end of the summer with the AC. Not sure what to do next, it sounds electrical, perhaps I should try getting a new fan switch??? Anyone have an issue like this and how did you resolve it?